Displays are ubiquitous and are a core component of wearable devices, smart phones, tablets, laptops, desktops, TVs and display systems. Common display technologies today range from Liquid Crystal Displays (LCDs) to more recent Organic Light Emitting Diode (OLED) displays and Active Matrix Organic Light Emitting Diode (AMOLED) displays.
Inorganic Light Emitting Diodes (ILEDs) are emerging as the third generation of flat display image generators based on superior battery performance and enhanced brightness. The ILED display has similarities to the OLED (organic LED) display in that it is self-emissive and current driven. The OLED concept is based on passing current through organic or polymer materials that is sandwiched between two glass planes to produce light. The ILED displays replace the organic LED material with a discrete standard LED (which is made of inorganic materials) at each pixel of the display (each pixel includes at least one Red, Green and Blue LED for color displays).
However, ILED displays differ from OLED displays in that the OLED material is fabricated or deposited directly onto the display substrate. In contrast, ILED devices are fabricated separately from the display. ILED devices' base material is grown on a crystalline carrier to form an LED starter wafer. This LED starter wafer is then processed through various steps to produce individual LED dies. Once fabricated the LED dies are assembled onto the display substrate to form the display or a display element, which is a part of a display comprising a plurality of LED dies positioned on a display substrate to form pixels or sub-pixels of a display. A final display may comprise one or more display elements.
The process of assembling (or manufacturing) a display element by transferring LED dies from a carrier substrate to a display substrate may include the use of a Pick Up Tool (PUT) that is configured to pick up LED dies from the carrier substrate, transfer them to the display substrate and place them on the display substrate, a process termed “pick-and-place.” The process used for the Pick-and-Place of LED dies in an ILED display is a factor in determining the time and the complexity of the display manufacturing process.